Dull and weighty field study (6)
I believe the answer is:
leaden
'dull' is the definition.
(I know that dull can be written as leaden)
'weighty field study' is the wordplay.
'weighty field' becomes 'lea' (lea can mean a meadow or field of grass. I am not sure about the 'weighty' bit.).
'study' becomes 'den' (term for a study or office).
'lea'+'den'='LEADEN'
'and' acts as a link.
Can you help me to learn more?
(Other definitions for leaden that I've seen before include "Heavy and slow, as if weighted down with heavy metal" , "Leaned over in slow, heavy way" , "Heavy or slow, like dark-gray metal" , "Describes grey overcast skies" , "Heavy - plodding" .)